ABSTRACT
I HOPE that the argument of the last five chapters will by now have become reasonably clear. But it is impossible to be completely sure about the force of an argument, however clear it may seem, until one has been able to work out its implications for matters with which it had not originally been concerned. This is true even if the argument is one’s own. So it would be as well if we turn in this chapter to one such question which has not so far come up for direct consideration, but on which our previous discussion must obviously have some bearing.
